Certain refrigerator appliances utilize sealed systems for cooling chilled chambers of the refrigerator appliances. A typical sealed system includes an evaporator and a fan. The fan generates a flow of air across the evaporator to cool the flow of air. The cooled air is then provided through an opening into the chilled chamber to maintain the chilled chamber at a desired set point temperature. Air from the chilled chamber is circulated back through a return duct to be re-cooled by the sealed system during operation of the refrigerator appliance, maintaining the chilled chamber at the desired temperature.
Certain refrigerators appliances include multiple freezer compartments configured for maintaining different temperatures for storing different types of food and drink items. For example, a conventional quad door bottom mount refrigerator can include a freezer chamber having two separate freezer compartments that are maintained at different temperatures. More specifically, a first freezer compartment may be maintained at a conventional freezer temperature (e.g., around 0° F.), while a second “convertible” freezer compartment may be adjusted between a conventional freezer temperature and relatively warm temperatures (e.g., between about 0° F. and 55° F.). A temperature of 55° F. within the warmed convertible freezer compartment may be useful for storing certain wines and other food items, for example.
However, achieving different temperatures in each of the compartments of such refrigerator appliances typically requires a separate evaporator for each compartment. In this regard, a single compressor may drive refrigerant through a switching mechanism to an evaporator configured for cooling a single compartment at a time. However, additional evaporators result in added costs, more complicated assembly, and a more complex refrigerant plumbing configuration. In addition, complicated switching mechanisms may be required or operational limitations may arise, e.g., only a single compartment may be cooled at a single time due to the shared compressor. Additionally, conventional refrigerator appliances typically include electric heaters for warming the convertible compartment to the desired set point temperature. Such electric heaters can be detrimental to energy performance.
Accordingly, a refrigerator appliance including a freezer chamber having a convertible compartment conditioned by an improved refrigeration system would be useful.